The present invention relates to a canister for fluid under pressure, of the disposable or throw-away container type, generally obtained by cutting and pressing of a relatively thin steel sheet which is protected from corrosion and oxidation by, for example, a tin coating or another coating.
By "fluid under pressure" is meant any substance or mixture of substances, in the liquid and/or gaseous state and under pressure. From among these fluids, and by way of example, mention may be made of a liquefied petroleum gas, in the pure state or in a mixture, such as commercial butane, having two phases, a liquid phase and a gas phase, under a pressure greater than atmospheric pressure and equal to the vapor pressure of the liquefied gas.
In general, these canisters have, on the one hand, a metal body having substantially the shape of a cylindrical shell, which shell delimits a circular opening at one end and is at least partly closed by a projecting dome at the other end, and, on the other hand, a metal recessed bottom closing the circular opening of the cylindrical shell and fastened in a sealed manner to the metal body by an annular crimp having the shape of an external bead. The latter connects, in a sealed manner, the straight edge of the shell delimiting the circular opening of the metal body to the straight foot of the recessed bottom, covering this straight edge.
From this general definition, it is then possible to distinguish:
perforatable cartridges, for which the cylindrical shell of the metal body is completely closed by a convex projecting dome at the end opposite the circular opening of said shell; and this projecting dome delimits, at its center, a region intended for the perforation, taking for example the shape of a hollow spherical cupola, in order to interact in a rigid and sealed manner with a perforator belonging to an apparatus for using or consuming the content of the cartridge, for example a cooking hotplate; PA1 cartridges with a valve, for which the projecting dome has, at its center, an opening which is closed, or designed to be closed in a sealed manner by a valve for drawing off the fluid under pressure, especially a valve of the aerosol-valve type; for example, the axial and circular opening includes a peripheral external bead onto which the annular and peripheral rim of the cup of an aerosol valve. PA1 via the circular opening of the cylindrical body, arranged "head down", with subsequent crimping of the recessed bottom; PA1 via the central opening of the projecting dome, for cartridges with a valve, with subsequent crimping of the valve. PA1 the upper cartridge is supported by the lower cartridge essentially in a region of the latter which is relatively poorly resistant to an axial point load, namely the projecting dome having a shape close to a sphere; on account of the charge contained by the cartridge, and therefore of its weight which may be relatively great, this drawback leads in practice to the number of cartridges which can be stacked one on top of another, for example for their storage or transportation, being limited; PA1 the stacking of at least two cartridges remains relatively unstable; this drawback is akin to the previous one and limits the possibilities of stacking the cartridges in question, for example on a is shelf for displaying these cartridges to customers.
All these canisters are well known to those skilled in the art, for example in the form of so-called aerosol cartridges. They may be filled in various ways, depending on the machines or equipment used, for example:
Of course, the present invention relates not only to the canisters defined above but also to these same canisters completely closed and filled with the fluid under pressure.
The present invention will now be introduced, defined and explained with reference to a canister of the cartridge with a valve type, containing, for example, commercial butane under pressure.
Conventionally, such cartridges with a valve comprise, on the one hand, a projecting dome of convex shape and, on the other hand, a recessed, concave or domed, bottom having, in diametral section passing through the axis of the body, the shape of a vault.
With this shape of the projecting dome and of the recessed bottom, stacking two cartridges results in bringing the valve of the lower cartridge into contact with the central part of the recessed bottom of the upper cartridge, limiting moreover the contact of the annular crimp of the upper cartridge with the projecting dome of the lower cartridge.
Under these conditions, two drawbacks may occur: